Tires generally classified as a radial medium truck (RMT) are used in a wide range of applications under a range of operating conditions. A pneumatic radial medium truck tire generally comprises at least one pair of parallel annular beads, at least one carcass ply wrapped around the beads, at least three belts or breakers disposed over the carcass ply in a crown area of the tire, a tread disposed over the belts or breakers, and sidewalls disposed between the tread and the beads. The majority of the belts or breakers in the tire are reinforced with steel filaments or cords, though the remaining belts or breakers may optionally be reinforced with organic polymer filaments or cords. The top belt or breaker may be, but is not necessarily, reinforced with organic polymer filaments or cords, depending on the particular end user application for the tire.
Optimally, the RMT tire has excellent high speed durability, good wear resistance and low rolling resistance, and generates relatively low heat and noise. The RMT tire is typically constructed in a manner which resists interlaminar shear strains which would tend to cause the tread crown to separate, but also is able to resist the radial or lateral forces during service which tend to tear the components between the belts. At the same time, the RMT tire must be able to maintain its rated operating specifications over prolonged periods of operation, even where high internal temperatures are generated which in turn tend to degrade the components in one or more tire layers during curing and service.
Typically, to maintain acceptable levels of stiffness, the RMT tire has traditionally incorporated resorcinol-containing resins which function to improve adhesion between the rubber formulation surrounding an included wire or cord and the wire or cord material. A stronger adhesive bond further imparts resistance to separation within the belt package between cord and belt for improved casing integrity. However, the use of resorcinol in the workplace is being discouraged, thus generating a need for substitute materials.